Value always return 0 while calculating [closed] - c++

Question

Closed. This question needs details or clarity. It is not currently accepting answers.
Want to improve this question? Add details and clarify the problem by editing this post.
Closed 8 years ago.
Improve this question
I was doing an assignment for my subject here and in the assignment, every student is required to create a simple C++ program. The problem here is, when I do not assign a default to a variable, a compile error will occur. However, when I assign a default value (in this case, value = 0), the value will always be 0.
My question is, is there any way to solve this problem while not encountering the compile error?
If there was a similar question asked, could you please also, include the link to the solved question as well? Thank you very much!
[Edit #1: To those who wonder why the code is "messy", I only used simple commands and did not use object oriented components, if/else statements etc. The project created was meant to be composed of "simple codes".]
[Edit #2: This is the output display that I snapped:
http://i.imgur.com/4csk1Rz.png
The Total Discounted fee part should be displaying numbers instead of default value 0]
(Microsoft Visual Studio Pro 2013; C++)
Expected output display:
http://i.imgur.com/jOJvymV.png
#include "stdafx.h"
#include <iostream>
#include <iomanip>
#include <cmath>
using namespace std;
int main()
{
/* Declare variables */
int qtyVehicleCar, qtyVehicleTaxi, qtyVehicleTruck; // User input
double feeOriginalCar, feeTotalOriginalCar, rateDiscountCar, feeTotalDiscountedCar, feeTotalAfterDiscountedCar; // variables for vehicle Car
double feeOriginalTaxi, feeTotalOriginalTaxi, rateDiscountTaxi, feeTotalDiscountedTaxi, feeTotalAfterDiscountedTaxi; // variables for vehicle Taxi
double feeOriginalTruck, feeTotalOriginalTruck, rateDiscountTruck, feeTotalDiscountedTruck, feeTotalAfterDiscountedTruck; // variables for vehicle Truck
double feeRepTotalOriginalFee, feeRepTotalDiscountedFee, feeRepTotalAfterDiscounted; // Generate final output
cout << "=====================================\n";
cout << "=====================================\n";
cout << "====== Malaysia Highway Company =====\n";
cout << "=====================================\n";
cout << "=====================================\n";
cout << endl;
cout << "Enter quantity of the vehicles on 1st January 2014: " << endl;
cout << "Car\t\t:\t";
cin >> qtyVehicleCar;
cout << "Taxi\t\t:\t";
cin >> qtyVehicleTaxi;
cout << "Truck\t\t:\t";
cin >> qtyVehicleTruck;
/* Lay out the Report table */
cout << endl << endl << endl;
cout << "Report\n";
cout << "--------\n";
cout << endl;
/* ============================== */
/* Declaration prior to process */
/* ============================== */
/* The problematic part
feeTotalDiscountedCar = 0;
feeTotalDiscountedTaxi = 0;
feeTotalDiscountedTaxi = 0;
*/
// Prices
feeOriginalCar = 2.00;
feeOriginalTaxi = 1.00;
feeOriginalTruck = 3.50;
feeTotalOriginalCar = feeOriginalCar * qtyVehicleCar;
feeTotalOriginalTaxi = feeOriginalTaxi * qtyVehicleTaxi;
feeTotalOriginalTruck = feeOriginalTruck * qtyVehicleTruck;
// In percentage
rateDiscountCar = 2;
rateDiscountTaxi = 10;
rateDiscountTruck = 15;
feeTotalAfterDiscountedCar = (rateDiscountCar/100) * feeTotalOriginalCar;
feeTotalAfterDiscountedTaxi = (rateDiscountTaxi/100) * feeTotalOriginalTaxi;
feeTotalAfterDiscountedTruck = (rateDiscountTruck/100) * feeTotalOriginalTruck;
// Final total - to be displayed
feeTotalAfterDiscountedCar = feeTotalOriginalCar - feeTotalAfterDiscountedCar;
feeTotalAfterDiscountedTaxi = feeTotalOriginalTaxi - feeTotalAfterDiscountedTaxi;
feeTotalOriginalTruck = feeTotalOriginalTruck - feeTotalAfterDiscountedTruck;
feeRepTotalOriginalFee = feeTotalOriginalCar + feeTotalOriginalTaxi + feeTotalOriginalTruck;
feeRepTotalDiscountedFee = feeTotalDiscountedCar + feeTotalAfterDiscountedTaxi + feeTotalAfterDiscountedTruck;
feeRepTotalAfterDiscounted = feeRepTotalOriginalFee - feeRepTotalDiscountedFee;
/* ================= */
/* Declaration END */
/* ================= */
/* Gives the following variables a default value, they will be modified later by the program */
feeTotalAfterDiscountedTruck = 0;
feeTotalDiscountedTruck = 0;
/* Processes */
cout << "Item\t\t\t\t" << "Car\t" << "Taxi\t" << "Truck\t" << endl;
cout << "------------------------------------------------------\n";
cout << "Original fee\t\t\t" << "RM " << feeOriginalCar << "\t" << "RM " << feeOriginalTaxi << "\t" << "RM " << feeOriginalTruck << endl;
cout << "Quantity\t\t\t" << qtyVehicleCar << "\t" << qtyVehicleTaxi << "\t" << qtyVehicleTruck << endl;
cout << "Total original fee\t\t" << "RM " << feeOriginalCar << "\t" << "RM " << feeOriginalTaxi << "\t" << "RM " << feeOriginalTruck << endl;
cout << "Discount rate\t\t\t" << rateDiscountCar << "%\t" << rateDiscountTaxi << "%\t" << rateDiscountTruck << "%\t" << endl;
cout << "Total discounted fee\t\t" << "RM " << feeTotalDiscountedCar << "\t" << "RM " << feeTotalDiscountedTaxi << "\t" << "RM " << feeTotalDiscountedTruck << endl;
cout << "Total after discounted fee\t" << "RM " << feeTotalAfterDiscountedCar << "\t" << "RM " << feeTotalAfterDiscountedTaxi << "\t" << "RM " << feeTotalAfterDiscountedTruck << endl;
cout << endl;
/* Displays output */
cout << "Total original fee\t\t:\t" << "RM " << feeRepTotalOriginalFee << endl;
cout << "Total discounted fee\t\t:\t" << "RM " << feeRepTotalDiscountedFee << endl;
cout << "Total after discounted fee\t:\t" << "RM " << feeRepTotalAfterDiscounted << endl;
cout << endl << endl;
/* Displays end line */
cout << "------------------- End of Program -------------------" << endl;
system("PAUSE");
return 0;
}

Answer 1

An uninitialized variables warning can mean either (1) you forgot to initialize something or (2) you thought you initialized it but didn't. Looks to me that in this case it's the second problem. Your variable names are mixed up.
For example,
feeTotalAfterDiscountedCar = (rateDiscountCar/100) * feeTotalOriginalCar;
feeTotalAfterDiscountedTaxi = (rateDiscountTaxi/100) * feeTotalOriginalTaxi;
feeTotalAfterDiscountedTruck = (rateDiscountTruck/100) * feeTotalOriginalTruck;
These are supposed to be the amounts of the discounts, no? So why are you storing them into feeTotalAfterDiscountedSomething rather than feeTotalDiscountedSomething?
Similarly,
feeTotalAfterDiscountedCar = feeTotalOriginalCar - feeTotalAfterDiscountedCar;
feeTotalAfterDiscountedTaxi = feeTotalOriginalTaxi - feeTotalAfterDiscountedTaxi;
feeTotalOriginalTruck = feeTotalOriginalTruck - feeTotalAfterDiscountedTruck;
Why is the third one storing the result into feeTotalOriginalTruck instead of feeTotalAfterDiscountedTruck? (Note also that if you fix the first problem above, the rhs of the subtraction will also need to change).
Also,
feeRepTotalDiscountedFee = feeTotalDiscountedCar + feeTotalAfterDiscountedTaxi + feeTotalAfterDiscountedTruck;
Similar problem. These should, I believe, all be feeTotalDiscountedSomething rather than feeTotalAfterDiscountedSomething.

Answer 2

The compiler rightfully complains that feeTotalDiscountedCar and feeTotalDiscountedTaxi are uninitialized. You need to initialize them somewhere. Maybe you want the user to enter them somewhere like this:
cout << "Discount Fee Total Taxi:";
cin >> feeTotalDiscountedTaxi;
cout << "Discount Fee Total Car:";
cin >> feeTotalDiscountedCar;

Answer 3

why are you setting them to zero just before printing out?
feeTotalAfterDiscountedTruck = 0;
feeTotalDiscountedTruck = 0;
It will show the error because you are trying to use the variable with out initializing it.